170 



s. GOTO. 



and filled witli a hyaline fluid. A step further onward in the same 

 direction would result in the formation of abundant fibres, and the 

 boiindai-ies of tlie oriji'inal cells would be partly absorbed and entirely 

 obliterated ; so that we should then have a ground-mass of irregular 

 fibrous substance, with miclei scattered therein — in fact just such a 

 form of mesenchyma as we really see in most parts of the b(xly of 

 Diplozoon. The lai-ge, round, vesicular ))odies above mentioned (Fig. 

 13) arc in fact the remnant cells of the original parenchyma, and the 

 poi'tion, already referred to. situated between the ovary and the testis, 

 seems to ha\(' tuulei'gonc ])ut little transf >rmati(^n. and to have pre- 

 served tlic original cclhdar structure. According to the view here 

 stated, the so-called j)seudocoel of tlie Trematodes would he not spaces 

 formed by the departing of the cells from one another leaving inter- 

 celhilar spaces between them, l)ut spaces which were before triil v infra- 

 cellular. I do not, indeed, entirely deny the presence of truly rnfer- 

 cellular spaces, but these ;u-e, 1 believe, comparatively insignificant. 



Similarly, of the two t\pical forms of Leuckart, the first results 

 apparently l)y a simple oblitei-ation of the boundaries of the original 

 cells. The second f >rm can be (lci'i\ed by a process similar to that 

 Avhich we have seen to ha\-e taken phice in Microcoli/le, in which some 

 of the cells (the larger vesicular ones) have maintained their cellular 

 natiu-e moj'e com])letelv, while others have been moi'e or less com- 

 pletely transformed into conne(;tive tissue, and j)ressed in, forming the 

 " Maschengewebe," between the former ; as already |)roved embry- 

 ologically by Schwarze. ^^ The two forms above mentioned, are con- 

 nected by numerous intermediate forms, and an actual transition 

 between them has been observed in some species."^ 



1) Schwarze — 1. c. p. 59. 



2) Looss — Beiträge zvir Kenntniss der Trematoden. Ztschr. f. \v. Zool. Bd. XLI. 1885. p. 

 432. 



